How do I exclude category from blog page

This code worked perfect for me with one change:

function exclude_category( $query ) {
    if ( $query->is_home() && $query->is_main_query() ) {
        $query->set( 'cat', '-17' );
    }
}
add_action( 'pre_get_posts', 'exclude_category' );

the ‘-‘ is not needed to remove the category, when the ‘-‘ was present it only displayed that category.

Here is the exact code used:

function exclude_category( $query ) {
    if ( $query->is_home() && $query->is_main_query() ) {
        $query->set( 'cat', '3' );
    }
}
add_action( 'pre_get_posts', 'exclude_category' );

I’m guessing that the ‘exclude_category’ and the ‘-‘ were two opposites which caused it to filter all except cat 3.

if I’m trying to apply the same code to a specific page how would I specify the page by name or ID instead of home.

Sorry I take that back.
I want to exclude categories after I click on a post on the blog page. So the post navigation (previous / next) needs to exclude posts of a specific category. BUT on another page the post navigation (previous / next) needs to exclude ALL other categories except the one I want (which was excluded from the blog page).

@frank
This is actually unrelated to this thread and there is another thread that already exists.
Can’t exclude a category from the previous_post_link and next_post_link
also reference:
Function Reference/previous post link
Function Reference/next post link

Thanks I found those but they don’t work, I’m sure it is a theme issue. I’m working on it from another angle.